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Renewable energy science fair project:
The effect of the number of solar panels and distance from light source on voltage output
and the speed of a solar-powered maglev train.

Science Fair Project Information
Title: Determine the effect of the number of solar panels and distance between the lamp and the maglev on the voltage and speed of the solar-powered pulley system maglev train.
Subject: Renewable Energy
Grade level: Middle School - Grades 7-9
Project Type: Experimental
Cost: Low
Awards: 2nd place, Canada Wide Virtual Science Fair (\$50)
Affiliation: Canada Wide Virtual Science Fair (VSF)
Year: 2010
Description: A homemade maglev train was powered by solar panels. The number of panels, in different configurations, and the distance of a lamp from the panels was changed and the resulting voltage and current and speed of the maglev train was measured. Results were tabulated and graphed.
Short Background

## Photovoltaic Array

A photovoltaic array (also called a solar array) is a linked collection of photovoltaic modules, which are in turn made of multiple interconnected solar cells. By their modularity, they are able to be configured to supply most loads.

The cells convert solar energy into direct current electricity via the photovoltaic effect. The power that one module can produce is seldom enough to meet requirements of a home or a business, so the modules are linked together to form an array. Most PV arrays use an inverter to convert the DC power produced by the modules into alternating current that can plug into the existing infrastructure to power lights, motors, and other loads. The modules in a PV array are usually first connected in series to obtain the desired voltage; the individual strings are then connected in parallel to allow the system to produce more current. Solar arrays are typically measured by the peak electrical power they produce, in watts, kilowatts, or even megawatts.

## Inverse-Square Law

The intensity (or illuminance or irradiance) of light or other linear waves radiating from a point source (energy per unit of area perpendicular to the source) is inversely proportional to the square of the distance from the source; so an object (of the same size) twice as far away, receives only one-quarter the energy (in the same time period).

For example, the intensity of radiation from the Sun is 9140 watts per square meter at the distance of Mercury (0.387AU); but only 1370 watts per square meter at the distance of Earth (1AU)—a threefold increase in distance results in a ninefold decrease in intensity of radiation.

The inverse-square law can be used only on point source light; a fluorescent lamp is not a point source and therefore one can not use the inverse-square law with a fluorescent lamp, although one can use it for many other light sources like an incandescent light bulb.

Source: Wikipedia (All text is available under the terms of the GNU Free Documentation License and Creative Commons Attribution-ShareAlike License.)

R=Reference
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Solar Energy (Cells & Panels) Resources R
Citation Guides, Style Manuals, Reference R
Electrical Safety R R

The Solar Car Book
A complete kit for making a cool solar racecar.
Everything is included: wheels, axles, motors, wires and a genuine one-volt solar cell.

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